"An agreement has been concluded with Exxon Mobil for exploration in northern Iraq," Erdogan was quoted as saying by the Hurriyet newspaper.

"This is a step taken with the regional Iraqi Kurdish administration," he added.

Erdogan, who began a key trip to the United States on Tuesday, also said that details of the partnership would be clarified during his talks with US officials.

The Turkish premier did not identify the Turkish company that is ExxonMobil's partner in the project.

On March 29, Erdogan said Ankara was discussing the terms of an energy partnership with Iraqi Kurds, in the first public confirmation of a project that could aggravate tensions in the powder keg region.

The partnership which runs parallel to Turkey's ambitions to become a regional energy hub threatens to worsen a long-running dispute between Baghdad and the autonomous Kurdistan region in northern Iraq over how to develop the country's energy wealth.

It is also raising eyebrows in Washington, where there are concerns that it could tip the volatile country towards disintegration and push an increasingly isolated Baghdad into Iran's embrace.

Erdogan has dismissed concerns and hailed Turkey's energy cooperation with Iraqi Kurds as "win-win" for both sides.

Ankara has been at loggerheads with the Baghdad government over a number of issues including Turkey's refusal to hand over fugitive Vice President Tareq al-Hashemi.

In November, Baghdad blocked Turkish national energy firm TPAO from bidding for an oil exploration contract, a decision which Erdogan had said was not "smart business."

And in December, Baghdad barred a plane carrying Turkish Energy Minister Taner Yildiz from landing in Arbil as he was reportedly on his way to seal the much-speculated energy deal.